(a) Field of the Invention
The present invention relates to an apparatus and method for managing a channel resource, and more particularly, to an apparatus and method for managing a channel resource, which are intended for channel hopping at a MAC (medium access control) layer and a PHY (physical) layer in beacon-based wireless personal network.
(b) Description of the Related Art
The most representative media access control (MAC) technology used to embody a service requiring a real-time property and a high reliability in a low power based wireless sensor network (WSN) system may support communication for an active duration after assigning an independent active duration according to a scheduling method.
For communication with another node device, a node device may receive data using carrier sense multiple access-collision avoidance (CSMA-CA) for a contention access period (CAP).
In a beacon-enabled operation mode, when a node device desires a deterministic channel access, the node device may be assigned with an independent time slot called a guaranteed time slot (GTS), and may perform the channel access. However, since such media access control (MAC) system employs a single frequency for a link usage period, the MAC system may be weak against an interference signal of the same radio frequency (RF) band and may not variably schedule a communication link bandwidth.
To solve the above issue in the MAC system using the single frequency, IEE802.15.4e standard proposed DSME (deterministic synchronous multi-channel extension) MAC, which is a channel access scheme using a time-slotted channel hopping protocol.
MAC frequency hopping (MAC FH) of DSME MAC is a channel hopping protocol used at the MAC layer, in which a node device transmits a data frame to a frequency channel set by a predetermined channel hopping sequence during each assigned time slot after passing through network connection and time slot assignment processes.
Meanwhile, PHY frequency hopping (PHY FH) has been used for the PHY layer in order to overcome physical degradation of reception signals, such as interference in a wireless zone and multipath channel fading. The PHY FH is a protocol in which multiple channels having a narrow bandwidth hop according to a predetermined channel hopping sequence.
The PHY FH is a protocol in which a single PPDU frame is divided into a plurality of subframes and the frequency hops in each subframe. This protocol is different from the MAC FH of the MAC changing the frequency channel in each frame. However, the problem of resource waste is caused because it is necessary for an upper layer of the MAC layer which manages a channel hopping sequence to have two hopping sequences for MAC-FH and PHY-FH in terms of resource management. Moreover, in the case that the network connection process and the time slot assignment process are separately carried out as in the DSME MAC, applications, such as a sensor network, requiring a network operation time of several years or longer, need a large overhead and therefore may require a large consumption of communication energy.